THE VERTEBRAL COLUMN AS A WHOLE 75 



long; of the axis, short; then extending in size until 

 the first thoracic is reached, thence diminishing to the 

 last dorsal, and becoming suddenly much longer in the 

 lumbar region. 



The intervertebral foramina are always in front 

 of the articular processes excepting those of the atlas 

 and the upper ones of the axis. They are named from 

 the upper of the two vertebrae which go to form them, 

 excepting in the cervical region, where there are eight, 

 the fissure between the skull and atlas being called 

 the first. The spinal canal is narrowest in those por- 

 tions having the least motion, viz., the dorsal and sacral 

 regions. It is round and f- of an inch in diameter 

 in the dorsal region; it is triangular, with the apex 

 behind, in the cervical and lumbar regions; and 

 largest of all in the cervical region. The cervical 

 vertebrae each have a foramen (costotransverse) in 

 their two transverse processes for the vertebral artery. 



FIG. 36 



Anterior 

 tubercle of trans- 

 verse process. 

 Foramen for vertebral 



artery. 



Posterior tubercle q 

 transverse process. 



'ransverse 

 process. 



Superior 

 articular 

 process. 

 Inferior 

 rticular 

 process. 



A cervical vertebra. (Gray.) 



General Characteristics of a Vertebra. A typical 

 vertebra is made up of two parts, an anterior solid 



